Save and Resume Form, and Update for User Profile?

I’m looking to create a form for member profiles on my site that allows our members to save and return to the form to complete it later, as well as to update information on their pages at will.

The basic form I’ve created to test out allows the page to be updated (no code, just a submission form connected to a database, which is connected to the member profile page). However, on later submissions any fields left blank result in blank spaces in the profile. Ideally, I’d like members to return to the form to see their previously submitted data already populated, and then only have to update input fields that need changing.

I would appreciate all the information anyone has on how to execute this! My experience with code is limited to Velo, and simple features I’ve already added to my site. However, I think I can catch on enough to make this happen if anyone has examples of similar code. Thanks in advance.